An organic light-emitting device (OLED) is a luminescence emitter by means of which electromagnetic radiation is produced from electric energy. The OLED has at least one organic active layer in which the electromagnetic radiation is produced. The active layer is arranged between an anode and a cathode. When a forward potential is applied, the anode injects holes into the active layer while the cathode injects electrons. The injected holes and electrons each drift (under the influence of an externally applied electric field) to the oppositely charged electrode and produce an electroluminescent emission on being recombined in the active layer.
A particular advantage of an OLED is that it can be used as a large-area and homogeneous light source. That allows totally novel applications as an illuminant. Commercially available OLEDs such as “ORBEUS CDW-031”, a product offered by the applicant, currently still have a relatively low light yield. The aim, though, is for substantially higher yields and luminance densities to be achieved in the future. However, a problem associated with size and higher luminance densities is that the OLED heats up inside. That gives rise to thermal effects such as, for example, ageing of the different functional layers. Temperature distribution not being homogeneous across a large-area component, the result can be different local ageing processes within the layers which, when the component is operated for longer periods, will give rise to increased inhomogeneities in luminance density. Inhomogeneities of such kind are, though, undesired.